The present invention generally relates to a portable device that includes a battery life indicator. More particularly, the present invention relates to a portable device, such as a flashlight, having a battery life indicator, which is configured to display the remaining battery life of the non-rechargeable batteries or rechargeable batteries powering the portable device.
Portable devices, such as flashlights, are often powered by non-rechargeable batteries. It is desirable to determine the battery life remaining in the non-rechargeable batteries and display this information on the portable device. Numerous types of non-rechargeable batteries and rechargeable batteries are available for use in a portable device and these numerous types of batteries often have different life times and different power discharge profiles for these life times. Similarly, these numerous non-rechargeable batteries and rechargeable batteries have different life times and different power discharge profiles for portable devices of varying load currents. As the different types of non-rechargeable batteries and rechargeable batteries often have different life times and power discharge profiles, providing relatively accurate information for remaining battery life in a non-rechargeable batteries and rechargeable batteries continues to be challenge. Furthermore, the assurance that most or all of the available energy has been consumed from batteries prior to disposal or recycling is of growing importance in today's “Green” marketplaces.
A number of portable devices, such as flashlights, have been developed that include battery life indicators. Each of the following listed U.S. patents describe portable devices having battery life indicators: U.S. Pat. Nos. 4,876,632, 4,962,347, 5,684,404, and 7,295,129. While a number of a battery life indicators for flashlight exist, an impetus remains to provide users with flash lights and other portable devices with battery life indicators that provide improved accuracy.